Allogeneic hematopoietic stem cell transplantation for acute leukemia.

Allogeneic transplantation is the only form of therapy that enables physicians to cure patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) who do not respond to induction therapy. Thus, patients and family members should be human leukocyte antigen (HLA)-typed soon after the diagnosis to expedite transplantation should induction therapy fail. Transplantation is superior to chemotherapy in patients with AML in second remission. The role of transplantation in ALL other than induction failure is somewhat different in children than in adults. Transplantation appears to be the treatment of choice in children with ALL in second remission regardless of the characteristics of the disease. Adults who relapse off-therapy after prolonged remission should probably be reinduced, whereas those with short remissions probably should go directly to transplant. Transplants from family members incompatible for one antigen result in survival rates similar to those observed with HLA-identical sibling transplants, but transplants from family donors mismatched for two or three antigens have been associated with a substantial increase in graft-versus-host disease (GVHD) and other complications and such transplants should be reserved for patients with few other prospects for cure. Randomized trials are underway to compare peripheral blood stem cells mobilized with granulocyte colony stimulating factor to marrow for H LA-matched transplantation. Results with unrelated donor transplants have improved with time and are approaching those for matched sibling transplants. Early results suggest that umbilical cord blood transplants are feasible with more graft failure but less GVHD than with unmodified marrow.